How to get rid of powdery mildew on plants

Powdery mildew is a fungal disease that is caused by different types of fungal species.

This disease is commonly found in hot and dry climates because in these climates the soil moisture is lower and humidity levels are high at the plant surface.

It’s symptoms look like white or grey dust. You will see them on the surface of leaves, buds, young shoots, fruits, and flowers.

Effect of powdery mildew on plants

Kale: Powdery mildew

  • The fungal disease won’t kill the host as they need water and nutrition to keep growing.
  • They cover the upper surface of the leaves sometimes the underside and turn it into yellow-brown and then black.
  • The fungus can also make some leaves twice, break or deform. 
  • If the growing fruits and vegetables get infected they might not produce a good or healthy yield.
  • They also affect the growth of herbs and flowers like roses, if your plants are infected by fungus they will grow slowly or might not grow.

What are the cause of mildew powdery

Okra: Powdery mildew

  • Improper air circulation

This fungal infection is also caused due to improper air circulation. Prune the foliage of the plants that get overcrowded, put them in an open area, and stalk long stems to provide the proper air circulation.

  • Not getting enough light

In the shade, there is more chance of powdery mildew. Transplant the plant in a sunnier spot, 

  • Wrong watering practice

Avoid watering from foliage. The common mistake everyone does, to water the plant from the top which wet the plant’s foliage. 

This is a wrong way to water, it can cause fungal infection.

You should always water in the plant base and save the upper part like stems, foliage, and flowers to get wet.

Powdery mildew Treatment

Powdery mildew is a common disease found throughout all plants. If this fungal spreads in the whole plant it can stunt growth and damage the flowers and fruits. 

Crucifers: Powdery mildew

But the good thing, you can easily cure this disease with home remedies.

If your plant is infected by this fungal disease on the surface of the leaves, fruits, and flowers you’ll notice white dust. 

  • Remove the infected parts

Remove or cut off all infected parts of the plant and destroy them. Destroy means burn or throw them away in the trash. If you leave them closer to the plant it might get transmitted through the wind.

  • Choose plant varieties that are resistant to powdery mildew. Many varieties of cucurbits like melons, squashes, cucumbers, pumpkin, etc are developed and brought from seed suppliers.
  • Treatment Milk: Many studies have proven that spraying milk on the plant surface prevents fungal diseases. Make a solution with 40% milk and 60% water and fill it in a spray. 

Sprinkle the solution on the plants every 10-14 days. This will reduce the chance of fungal infection to grow again.

How to prevent from powdery mildew

Fungicides

To prevent this fungal disease apply protectant (preventative) fungicides on the plants.

  • Organic Fungicides like neem oil, sulfur, lime-sulfur, and potassium carbonate. 
  • These Fungicides are most effective at the beginning of the fungus or when you first notice them.
  • If the fungus spread around the whole plant it is very difficult to get rid of them. 
  • In that case, the best thing is to protect other plants in the garden. 
  • The mildew powdery is often spread from air and insects like aphids. Do treatment of the plant as discussed above.

Bicarbonate solution

If you don’t want to invest in fungicides you can use a homemade remedy called bicarbonate solution.

  • Take 1 teaspoon of baking soda in 1 quarter water. 
  • Fill the solution in the spray and apply it to the plant.
  • For safety first, spray it on one infected part of the plant and wait for 2-3 days if you don’t notice any reaction. 
  • Spray thoroughly the solution to other parts of the plant as it kills when comes in contact with the fungus.

Sulfur

Sulfur is the most effective and least expensive product you can use to prevent fungal disease.

  • Apply sulfur on plants that are prior to or susceptible to fungal disease.
  • Some sulfur products instruct to spray them directly to infected plants but the results vary from different plants.
  • For gentle or young plants like herbs and flowers, the best practice is to mix the sulfur with water and spray it on the plant. This reduces the risk of any harm.
  • The sulfur product should be applied after the rain, the plant’s foliage gets wet. 

Squash: Powdery mildew

However, this only depends upon the variety of the plant. Hardy plant variety won’t need that much care but tender plants do.

  • Do not treat the plant with the sulfur product if you have applied horticultural oil wait at least 2 weeks. Horticultural oil itself is used for pest control. Appling lots of products at once might not suit the plant.
  • Also, apply it only then the temperature is below 80o F. As you know sulfur is a spontaneous metal, overheat can burn the plant.
  • Many gardeners use brush or dust products on the foliage of their plants, but the sulfur products can cause irritation to the eyes and throat. They are also not suitable for all types of plants.

Caution: Read instructions on the packet carefully and wear gardening gloves before applying them to plants. You should avoid using them in certain types of plants like melons, apples, grapes, and squash.

Copper

  • Copper may be an effective fungicide against powdery mildew and may also control some types of bacteria but experts say it is not as effective as sulfur.
  • You can apply copper products similar to sulfur by mixing them with water and spray onto plants.
  • Apply copper product as soon as you observe some fungus is thriving on the plant.
  • Spray three times every 7-8 days and after the rain. 
  • When you notice the fungal get controlled stop applying.
  • Similar to sulfur, copper products also cause skin and eye irritation. Wear gardening gloves and cover your body before using copper products. 
  • Also, keep in mind these products don’t give similar results to all plants. So, thoroughly read the instructions behind the packet.

Final thought

Do not worry if your plant gets infected with powdery mildew. It is a common problem faced by every gardener. 

Just take appropriate steps as explained above and wait with patience. 

Your plant will soon get cured and start growing like nothing has happened.

However, if your whole plant gets infected including stems and foliage then you might have to toss them off and begin with a new one.

So keep observing your plants and when you suspect danger of fungus take immediate cure action.

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